A Highly Selective and Sensitive Fluorescent Chemosensor for Aluminum Ions Based on Schiff Base

Area of Science:

• Analytical Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Fluorescent chemosensors are crucial for detecting metal ions.
• Schiff base compounds offer versatile platforms for sensor development.
• Aluminum ions (Al3+) play significant roles in biological and environmental systems, necessitating accurate detection methods.

Purpose of the Study:

• To design, synthesize, and evaluate an efficient "off-on" fluorescent chemosensor for Al3+ detection.
• To investigate the sensing mechanism based on the chelation-enhanced fluorescence (CHEF) effect.
• To assess the selectivity and sensitivity of the developed chemosensor towards Al3+.

Main Methods:

• Synthesis of the Schiff base chemosensor (E)-N'-(4-(diethylamino)-2-hydroxybenzylidene)-2-hydroxybenzohydrazide (H2L).
• Fluorescence spectroscopy to monitor the interaction between H2L and various metal ions.
• Determination of the complex stoichiometry and binding affinity.
• Computational studies to understand the recognition mechanism.

Main Results:

• The chemosensor H2L exhibited an "off-on" fluorescence response upon binding with Al3+.
• A significant 45-fold fluorescence enhancement was observed due to the CHEF effect.
• The sensor demonstrated high selectivity for Al3+ over a range of other metal ions.
• A low detection limit of 3.60 × 10^-6 M for Al3+ was achieved in an EtOH-H2O solution.

Conclusions:

• The synthesized Schiff base H2L is a highly efficient and selective fluorescent chemosensor for Al3+ detection.
• The CHEF mechanism is responsible for the enhanced fluorescence signal.
• The developed sensor holds potential for practical applications in Al3+ determination.